Thursday, July 12, 2012

Children and Ionizing Radiation

HISTORICAL AND CONTEMPORARY DISCUSSION OF THE STUDY OF THE BIOLOGICAL EFFECTS OF IONIZING RADIATION ON CHILDREN (authored by me):

Research on the effects of ionizing
radiation on children particularly mobilized public distrust of the U.S. Atomic Energy Commission (AEC).
British epidemiologist Alice Steward of Oxford University raised awareness of
the harmful effects of X-rays on human fetal development and childhood leukemia
in her groundbreaking work published in the late 1960s and early 1960s.
Children born to mothers who had X-rays during pregnancy had a forty percent
increase in incidents of leukemia and other cancers.[i] Ernest
J. Sternglass followed Steward’s work. In 1963 he published in the journal Science a research paper titled:
"Cancer: Relation of Prenatal Radiation to Development of the Disease in
Childhood" in the journal Science.[ii]In 1969, he publicized his research by arguing in Esquire Magazine that radioactive fallout from atmospheric testing
had caused the death of 375,000 infants less than a year old and countless
fetal deaths between 1951 and 1966.[iii] In
1972 Sternglass published Low-Level
Radiation, re-titled in 1981 Secret
Fallout: Low-Level Radiation from Hiroshima to Three Mile Island.

Not surprisingly Sternglass’s argument drew
controversy, although his most pointed critic, Arthur R. Tamplin, did not
dispute that fallout deaths had occurred, but disagreed with Sternglass about
the magnitude of them. Tamplin calculated eight thousand fetal deaths and four
thousand infant mortalities.[iv] Although
he was disputing Sternglass’s estimates, the AEC attempted to censor his report
by asking him to withdraw his mortality calculations, fearing the public would
find them alarming. Tamplin’s subsequent research on the health effects of
nuclear power earned him more enmity. However, he had support at Lawerence
Livermore Lab where he worked from John W. Goffman. In 1969 they argued
together in a research paper that seventeen thousand additional cases of cancer
annually would derive from the permissible lifetime
dose of 0.17 rads per year.[v]
They argued for lowering the permissible dose.

Tamplin’s and Goffman’s proposal for
lowering the permissible dose drew significant criticism for presuming that all
levels of ionizing radiation exposure cause effects. Their position conflicted
with the “threshold” theory still promoted by the AEC that held that ionizing
radiation did not cause harmful somatic or genetic effects below a specific
threshold. The critics charged that Goffman and Taplin had inappropriately used
known health effects for high doses of radiation to derive estimates for the
effects of low doses of radiation. At issue in the debate about threshold was
the idea that long-term exposure to low-doses of radiation causes the same
effect as acute exposure to high levels of radiation, especially for children.

However, the public was growing
increasingly alarmed about the relationship between radiation and cancer,
especially after the March 28 accident at the Three Mile Island nuclear plant
in Pennsylvania. Indeed, an article in TheNew York Times published on page 1 of
the July 1, 1979 issue was titled “Public Fears Over Nuclear Hazards are Increasing:
Low-Level Radiation: How High the Risk.” The article notes “From New York to
Washington State, from Texas to Montana, people are edgy, if not outright
angry, over radiation … over potential hazards that exist, in some cases,
literally in their own backyards.” In 1980, Harvey Wasserman and Norman Solomon
wrote (in consultation with Robert Alvarez and Eleanor Walters) examined some
of those ubiquitous risks in Killing Our
Own: The Disaster of America’s Experience with Atomic Radiation. The book
examined the dangers of artificially produced radiation across a variety of
contexts ranging from nuclear fallout from atmospheric testing to the
“industrial underside” of bomb production in Colorado, uranium milling in
Church Rock New Mexico, and Tritium from American Atomics in Tucson Arizona.
This book challenged the idea that the permissible dose was safe and sensitized
the public to a wide array of sources of unsafe exposure.

To this day conflict exists about the
legitimacy of a permissible dose for guaranteeing public safety, especially for
those populations living in close proximity to nuclear power plants. It is
instructive to examine briefly some current findings on the health effects of
children’s exposure to ionizing radiation across three areas of research:
proximity to nuclear plants, medical imaging, and background radiation.

Recent research on nuclear plants and
childhood leukemia suggest that ongoing plant releases may cause cancer in
children residing in close proximity to the plant. A study by the Institut
National de la Sante et de la Recherche Medicale (French Institute of Health
and Medical Research, or INSERM) documented a leukemia rate twice as high among
children under the age of fifteen living within a five kilometer radius of
France's nineteen nuclear power plants as compared to the rate found in the
child population living twenty kilometers or more away from the plant.[vi]
The French study reinforced previous findings on excess risk for leukemia in
young children living in close proximity to German nuclear power plants.[vii]
In a commentary, “Childhood Cancer near Nuclear Power Stations,” published in Environmental Health Perspectives, Ian
Fairlie observed: “Doses from environmental emissions from nuclear reactors to
embryos and fetuses in pregnant women near nuclear power stations may be larger
than suspected. Hematopoietic tissues appear to be considerably more
radiosensitive in embryos/fetuses than in newborn babies.”[viii]

Exposure to tritium may be the
primary agent culpable for cancer and leukemia. Water that cools reactor cores
and spent fuel pools becomes extensively contaminated with tritium.[ix] Tritium
is a radioactive isotope of hydrogen with a 12.32 half-life. Tritium emits beta
particles (high speed electrons) as it decays. It is very difficult to contain
and is therefore nearly continuously emitted from nuclear power plants. It
binds with oxygen and ends up in precipitation and water supplies, where it can
be inhaled or ingested. It can also be absorbed through the skin. Harrison and
Day describe the biological effects of tritium in their article “Radiation
Doses and Risks from Internal Emitters”

low energy beta emissions from
tritium (3H) decay have been shown to have RBE (ratio of the absorbed dose)
values of up to between 2 and 3 (compared to gammay rays), for in vitro end-points
including cell killing, mutation and
induction of chromosomal aberrations.[x]

Evidence of tritium contamination can be found in Clyde
Stagner’s Hidden Tritium, which
examines tritium emissions from spent fuel pool evaporations at the Palo Verde
Nuclear power plant located near Phoenix. His calculations of evaporation rates
and accumulation of tritium in precipitation, based on EPA data and analysis of
evaporation rates conducted by Arizona State University, document risks posed by
the beta emitter to populations throughout the Phoenix area. Stagner
illustrated the risks graphically in an analysis of tritium concentrations in
public swimming pools in Phoenix. Accordingly, "Swimming 2 hours a day
during a six month swimming season results in a dose of . . . 1.927
millirem. Swimming 2 hours a day annually results in a dose of 3.908 millirem."[xi]
This dose exceeds the As Low as Reasonably Achievable dose of 3 millirem.[xii] In
2011 the EPA discontinued its monitoring of tritium in Phoenix despite evidence
of steadily growing accumulation of the isotope in the local environment across
time. Tritium has been linked to chromosomal breaks, brain tumors, ovarian
tumors, decreased brain weight in offspring, and mental retardation in animal
studies.[xiii]

Another area of investigation of the
biological effects of radiation on children concerns medical imaging. Studies
on medical imaging show children are very vulnerable to the radiation used in
the imaging. A study published in The
Lancet in 2012 found that CT scans cause a small but significant increased
risk for leukemia and brain cancer.[xiv]
Two to three scans of the head for children under three tripled the risk for
brain cancer as compared to the general population while five to ten scans
tripled the risk for leukemia. A study of adults found that “For every 10 mSv of low-dose ionizing
radiation, there was a 3% increase in the risk of age- and sex-adjusted cancer
over a mean follow-up period of five years(hazard ratio 1.003
per milliSievert, 95% confidence interval 1.002–1.004).[xv]

Finally, recent research has
documented that even background levels of radiation can cause cancer in
children. One study addressing background gamma radiation found a twelve
percent increase in childhood leukemia for every millisievert of natural
gamma-radiation does to bone marrow.[xvi] This
study demonstrates that low dose gamma radiation can cause produce genetic
changes significant enough to cause leukemia. One area of DNA particularly vulnerable
to background radiation is mitochondrial DNA. An innovative study examined how
naturally occurring high background radiation produced mitochondrial DNA
mutations that were transmitted across generations:

The observation that radiation
accelerates point mutations at all is unexpected, at first glance, because
radiation was, until recently, thought to generate primarily DNA lesions (1). A
potential explanation is provided by our additional observation that these
radiation-associated point mutations are also evolutionary hot spots,
indicating that the radiation indirectly increases the cell's normal
(evolutionary) mutation mechanism (5).[xvii]

Mitochondrial damage transmitted across generations could
eventually result in a level of inherited damage capable of compromising this
vital cell function. Children are thus vulnerable not only because their DNA
appears more vulnerable but also because they have inherited all the germ-line
genetic damage from previous generations.

Taken together these studies demonstrate
that common forms of exposure to ionizing radiation can cause cancer and
leukemia and that genetic damage can be transmitted across generations.
Moreover, they demonstrate that children are particularly susceptible to
detrimental effects. The studies are significant because they suggest that
current estimates for dose-risks may under-estimate actual risks.

The 2006 BEIR report, Health Risks
from Exposure to Low Levels of Ionizing Radiation produced by the National
Research Council of the National Academies predicts cancer rates at different
levels and ages of exposure for males and females (see Goddard's Journal for analysis http://www.iangoddard.com/journal.htm). For instance, the report
predicts that at 0.1 grays (which equals 100 millisieverts) of exposure the
lifetime attributable risk (LAR) of solid cancer incidence and mortality for
male children at age 10 would be an increased rate of cancer of 1330 and
increased mortality rate of 640 per exposed 100,000 people. For female children
at age 10 this same level of exposure would produce a 2530 increased incidence
of cancer and a 1050 increased incidence of mortality.[xviii]
The risk would multiply with every year of exposure subsequently. However, the
report introduces uncertainty in risk calculations based on internal exposure and
on the effects of protracted low-dose exposure.[xix]
The report notes that ingested alpha particles are more effective than low LET
radiation (e.g., gamma rays) in produce genomic instability and that “at low
doses, the effectiveness per unit absorbed dose of standard X-rays may be about
twice that of high-energy photons.[xx]
The effectiveness of lower-energy X-rays may be even higher. How this
translates into risks of late effects in man is an open question.”[xxi]

The studies reported in this section
suggest that the BEIR report may under-estimate risk, especially for internally
ingested radioisotopes. Two other sources of data about radiation risks also
suggest that the BEIR tables under-estimate risk. First, epidemiological
research on the effects of Chernobyl indicate significant somatic health
effects at exposures not predicted to produce them, although the conclusions
are hotly contested. Second, in vitro studies on the effects of ionizing
radiation, particularly alpha particles, on cell biology and DNA mutations
indicate that extremely low levels of exposure can have mutagenic effects.

[xi] Clyde Stagner personal
correspondence. Stagner provided me the data and analysis he sent to the EPA
expressing concerns about the excess exposure to tritium in Phoenix
precipitation and bodies of water, including swimming pools.

About Me

I am a Professor at a large public university. I study political economy and biopolitics (the politics of life). My interests are diverse but are broadly concerned with economic, social and environmental justice. I have published 5 books: Crisis Communication, Liberal Democracy and Ecological Sustainability: The Threat of Financial and Energy Complexes in the Twenty-First Century (2016); Fukusima and the Privatization of Risk (2013); Constructing Autism (2005); Governmentality, Biopower and Everyday Life (2008/2011); Governing Childhood (2010).
I also participated in an edited collection on Fukushima: Fukushima: Dispossession or Denuclearization (2014).